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In this question, when given a principal sum of $3 ,500 is invested at 5 .5 % interest compounded annually, we want to find the number of years it would take to accumulate $5 ,000 or more in the account.
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Now, the compound interest formula is a is equal to p times 1 plus r over n to the power nt.
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A is the amount, that is the principal sum plus interest.
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P is the principal sum.
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R is the interest rate per annum in decimal.
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N is the number of times interest is compounded per year.
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And t is the time period in years.
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So our p here is $3 ,500.
00:51
Our r here, interest rate, is 5 .5%.
00:55
And now divide by 100, you'll get a decimal, which is 0 .055.
01:02
And our n, number of times the interest is compounded per year.
01:08
Compounded annually means compound one time per year, so n is 1.
01:12
And our a will be $5 ,000...